The EDP or PPA itself
The commitment, the term and the discount. What usually decides the deal is which spend counts as eligible, how the discount stacks with your Savings Plans and Reserved Instances, and what happens in a year you fall short. Savings Plans and RIs apply first, so the EDP percentage lands on the already-discounted bill: 10% off a bill that Savings Plans cut from €800k to €380k is €38k, not €80k.